New Delhi, March 5 -- When Warren Buffett lambasted US President Donald Trump's imposition of tariffs as "an act of war to some degree," he wasn't wrong. Of course, there's no conventional battle going on. But hard blows characteristic of warfare are being exchanged in the field of trade.

As an additional 10% tariff on China came into force on Tuesday-on top of 10% slapped on it earlier-China announced reciprocal tariffs on a raft of American agricultural and other products. Canada too responded to action against it with a tit-for-tat 25% levy on US imports worth $107 billion. And Mexico indicated its readiness to respond as well, although its plan isn't clear, to a similar barrier erected by the US against it.

What seems certain, howev...